It's clearly a major incident and involves children. Horrible.
I've been expecting some sort of attack during the run up to the election because, sickeningly, major disruption in so many disparate groups' interests. Will have to wait to see if this is an attack (seems likely now), and what sort, by whom (given the two recent German incidents of false-flagging).
And watch ALL the groups who hope for publicity or to benefit, enjoying themselves, regardless of who the actual murderers are.